Search Results

An actuator has been developed and qualified with all loop-closure and redundancy management functions covered by an electronic package physically located on the actuator manifold assembly. The actuator meets or exceeds all Original Equipment Manufacturer (OEM) requirements of the F/A-18 aileron servocylinder design with the single restriction of 99 °C (210 °F) maximum oil temperature. While the actuator has performed well at temperatures in excess of 135 °C (275 °F), present MIL-SPEC derating for electronics limit the allowable operating range. The basic design offers potential advantages in the areas of weight, maintainability, self-diagnostics, and ease of integration.

The reaction of ethylene in engine exhaust gases has been studied using a turbulent plug flow reactor. The effects of ethylene, oxygen, and nitric oxide concentrations and of temperature on the reaction were investigated. Nitric oxide was found to be consumed in the reaction and partially converted to nitrogen dioxide. For temperatures up to 649 °C, little formation of carbon dioxide was measured for a reaction time of 140 ms. Increasing the oxygen concentration above 4% gave no increase in the oxidation rate. The Kinetics of the reaction were such that it was not possible to describe the reaction with a simple Arrhemus rate expression. The only other hydrocarbon found was a trace of acetylene at a reaction temperature of 649 °C.

Methods used for the study of the kinetics of exhaust hydrocarbon reactions are reviewed, compared and contrasted. The isothermal plug flow reactor which allows the determination of time resolved concentration histories of reactants, intermediate products, and final products is suggested as, perhaps, the most desirable and versatile system for the study of moderate temperature hydrocarbon oxidation reactions. The isothermal plug flow reactor allows the gas phase reactions to be studied with kinetically well-defined, repeatable, homogeneous reaction conditions that are essentially free of heterogeneous interference. Due to the detailed data obtainable and the controlled reaction conditions, kinetic mechanisms can be studied and evaluated. Investigations that used this technique are reviewed and examples cited to demonstrate the unique capabilities of the plug flow reactor.

The objectives of this study are twofold. First, engine data are presented which indicate how the three major automotive exhaust pollutants are affected by the distribution of the inducted fuel. Nonuniform fuel distribution prohibits lean engine operation without increasing hydrocarbon emissions. Nitrogen oxide emissions are lower at a given fuel-air ratio with nonuniform fuel distribution, this condition being particularly true near stoichiometric conditions. Carbon monoxide emissions are lower with more uniform fuel distribution. The primary objective of this paper is to demonstrate a new method of studying the mixing conditions that take place in an induction system. This method involves the use of a conventional water table, a facility to demonstrate pictorially the salient flow field characteristics and mixing patterns that were encountered at typical engine operating conditions. Also, several different geometric configurations and their resultant flow patterns are included.